


Growing Pains

by VivianDarkbloom05



Category: Kuroshitsuji | Black Butler
Genre: Canon Compliant, M/M, Oral Sex, Plot What Plot/Porn Without Plot, fbi open up
Language: English
Status: Completed
Published: 2020-01-11
Updated: 2020-01-11
Packaged: 2021-02-27 06:22:37
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, Underage
Chapters: 1
Words: 1,805
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22212502
Author URL: https://archiveofourown.org/users/VivianDarkbloom05/pseuds/VivianDarkbloom05
Summary: The butler’s eyes gleamed in satisfaction, pleased to notice that Ciel had already shucked off his breeches prior to Sebastian’s undressing. The demon really could not wait to devour him: mind, body and soul. And there were more ways than one to "eat" him, so to speak.
Relationships: Sebastian Michaelis & Ciel Phantomhive, Sebastian Michaelis/Ciel Phantomhive
Comments: 3
Kudos: 119





	Growing Pains

**Author's Note:**

> This is my first Kuroshitsuji fanfic, but I've loved these two since forever. Hope you like it!

_Sebastian._

The butler called Sebastian sat up from its cot, alerted by its master’s summons. A demon’s body did not sleep or need respite like a human’s, but this particular demon was currently playing an act. One of a devoted servant to an imperious earl. It stretched its limbs as if actually rousing from slumber, garnet eyes glowing faintly in the blue night. 

The faithful servant was in its master’s chamber within seconds. The restless earl was tossing and turning in his bed. Sweat marred his brow, his cheeks flushed. 

The boy’s mismatched eyes were glazed and unfocused. He called for his butler again weakly.

“Sebastian.”

“My lord? Bad dream, perhaps.”

It bowed mockingly, its lips curled into a mischievous smile. For it would know even from a mile away what was ailing the young lord so. The demon was simply content to play along if his charge wished it.

The earl’s stare could drill holes in Sebastian’s skull. He looked at him scornfully, knowing fully well that his butler understood what was happening to him. He hated it, the growing heat pooling in his stomach. Even the slightest friction from his blanket could make him see stars. He tried squeezing his legs together but that just made it even worse. He even tried touching it, the aching thing between his legs, but to no avail. It just wouldn’t stop…aching. No matter what he tried. In the back of his mind he knew he needed something more, but he was simply too young to know what it was. 

But one thing was for certain. He had woken up in his own pool of sweat, his mind conjuring up images of his butler. He dreamt of _his servant, of all people._ Ciel had thought himself completely mad, sick to his stomach. But also very aroused.

He tried not to dwell on the thought that his first wet dream was Sebastian and tried to simplify it in his mind: he was uncomfortable, and there was nobody else in the world he trusted like Sebastian. He let the duvet fall, no longer hiding himself. 

“I - It won’t go away. I don’t want to take care of it on my own.”

Sebastian was very pleased to hear the admission. But he also knew his master was very much like a cat, and a particularly skittish one at that. He could be bold this instant and come running for the hills the next. So, in the interest of preserving his young master’s dignity, Sebastian whispered softly in the candlelit dark.

“Lie back, young master. Close your eyes and think of Miss Elizabeth.”

Sebastian laughed softly to himself, knowing with full certainty that they both knew the young master’s cousin would be the farthest thing from his mind tonight. 

The earl did as he was told, his eyelids fluttering slightly from the force of being shut so tight. The demon would have been breathless if it had needed air to live. Here was its little emperor, pliant and submissive like never before. Sebastian leaned in and placed a tender kiss on his pale neck. Small hands thumped at the creature’s back in protest.

“Just. Get it over with.” 

Ciel choked, struggling to get the words out. The butler, ever obedient, lifted the loose white nightshirt free from the young earl’s lean body. Ciel shivered in the night air, goosebumps raising in his arms. 

“Relax, my lord. Let me take care of everything.”

Sebastian drank in the sight of its young master’s frail but growing body. The butler’s eyes gleamed in satisfaction, pleased to notice that Ciel had already shucked off his breeches prior to Sebastian’s undressing. _Ah, youth. How delicious._

It really could not wait to devour him: mind, body and soul. And there were more ways than one to _eat_ him, so to speak. Sebastian began its assault on Ciel’s pebbled chest, sucking on one of the rosebud pink nubs while its fingers twisted and toyed with another. 

_Ah!_ Ciel arched his back at the foreign pleasure, flat chest pressing more into Sebastian’s preoccupied mouth. Sebastian twisted the boy’s nipples torturously, the demon comparing the flushed hue to a cat's soft, pink paw. Sebastian groaned in satisfaction when the earl began to rut himself against its trousers. 

The young earl was a pleading, angry mess, hurling curses and demands at Sebastian. Sebastian, however, was unfazed and paid no heed to the commands. It did not hasten its leisurely pace. Sebastian’s tongue would lick a long, lazy trail from Ciel’s breastbone to his belly button. The demon’s tongue would dip into the hollow, the butler internally smirking as the earl’s empty threats slowly dissolved into pleas for more. 

When the butler had satisfied itself with the taste of the exposed skin offered, it finally decided to dive into the main course. Sebastian enveloped the weeping pink cock in his fist, pumping it lightly. 

“Sebastian!”

Ciel yelled in pleasure, fingers threading themselves into the demon’s coal black strands. Sebastian took care not to let its little master orgasm just yet, making sure its movements were pleasurable yet not enough. 

Sebastian’s mouth watered at the sight of its master’s throbbing member. It had grown considerably but was still underdeveloped, fine downy hair forming at the base. Sebastian’s tongue teased the slit, collecting the pearly fluid gathering there. 

Ciel bucked his hips roughly, making Sebastian chuckle. Hands pinned the boy’s hips in place, and Sebastian savored the sounds of desperation and frustrated pleasure above it. 

“Fuck, you filthy scum. How dare you deny your master—“

Sebastian tut-tutted, the demon’s scarlet orbs dancing with amusement. The villain traced one black nail along the protruding vein in Ciel’s cock, clearly admiring the view.

“It pleases me that my young master has grown so much.”

The demon could’ve had more than enough of its fill of verbal abuse from its imperious young master, had its mouth not enveloped its master’s entire cock in a swift bob of its head. Ciel thrashed and howled in ecstasy, already close and overstimulated to tears. 

Sebastian purred against the cock in its mouth, appreciative of the size and feel of its young master’s arousal. Sebastian mused in its head that it was the perfect size for oral sex, not quite developed to its full potential. The girth stretched the demon’s mouth only slightly, making it look as if the devilish servant was only indulging on a sweet lolly. 

“Ahh…Nnn—Sebastian, I’ll—Haah!”

Sebastian let the pink cock loll from his mouth with a lewd pop, effectively stunting the boy’s impending orgasm. Sebastian was almost surprised at its own cruelty, astounded at how it had been so careful before and was now being reckless. But the boy always had that effect on the demon—there was only so much the butler Sebastian could endure before all its self control eventually ran out and the hell spawn known to some as Sebastian Michaelis came to play. 

“Seba—Ah! Why!”

The little earl whined in pleasure and pain, frustrated at the sudden withdrawal of his orgasm. 

“All good things come to those who wait, my lord.”

The boy was flipped onto his back, pert rump exposed to the lust filled gaze of the unraveling demon. Said demon licked at the boy’s entrance, the boy’s form jolting in revulsion and protest. 

“Sebastian! What—sstop…ah! It’s dirty! That’s an ord—“

The words died in his throat. Sebastian plunged a now forked tongue deep into the boy’s hole, stretching the tight, unmolested cavern. Sebastian lathed the hole with spit and lubrication, making sure to prepare the young body for any intrusion. He was still tight, and much too tense for anything other than a finger. _Ah, of course. That will have to wait._ The demon mentally chided itself for taking things too far, and its fangs dug into its still human lips sharply, drawing blood. 

Ciel’s panting and incoherent commands broke the demon from its reverie, remembering its charge beneath him. His own butler had ruined him beyond salvation and still, he was begging for more. The demon finally took pity on the young earl, sucking the painfully hard cock in his mouth dry. 

He fucked into his butler’s greedy mouth until he no longer could. Ciel cried out as he came, his butler drinking in every drop of its master’s precious essence.

Ciel took stock of his butler’s slightly altered form, his eyes settling on the growing obsidian antler-like horns on its head. 

Curious, Ciel reached out to stroke one of the horns. Sebastian took the boy’s hand and kissed it reverently, the gesture in stark contrast to the rough treatment the demon had been doling out mere moments ago. The devil led the boy’s dainty hand to rest on its own engorged cock, guiding the boy’s hand to make pumping movements.

“Ah…Master—apologies, I’m at my limit.”

Sebastian came with the boy’s gaze boring into its soul, stroking him like he would a pet. Ciel stretched out his hand in front of Sebastian, silently commanding the demon to clean up its own mess.

Sebastian tongue darted out to suck on its master’s digits, its mouth mimicking the movements it had made on the earl’s cock previously. Sebastian delighted in the audible gasp that followed. 

****

The butler brought out a washcloth in lieu of drawing its master a bath. The boy was too exhausted and boneless to stand up, let alone move a muscle.

Sebastian laid on fresh sheets and tucked its master to sleep. It placed a kiss on the growing boy’s forehead, not unlike a governess with her favorite charge.

It was not human, no matter how convincingly it masqueraded as one. The creature would never understand attachment. But it understood devotion and fierce loyalty. His young master was innocent yet jaded, corrupted but pure. He was simply exquisite, a sumptuous feast like no other.

Still, the demon could not help but wonder if it could survive solely on its master’s lifeblood for another century or two. Perhaps it could survive on little bites of Ciel? This line of thought was particularly odd, especially for a demon of Sebastian’s caliber. Truth to be told, Sebastian would not mind a few more centuries with this contractor. 

Besides, it knew for a fact that there would simply be no one else after Ciel. The demon would most likely go mad, gorging itself with unworthy mortal souls after indulging in such a masterpiece. _Everyone else would simply be unworthy after this soul._

But what could it do? The ravenous demon whose name was Sebastian pondered. _A beast had to eat after all._ It could not help itself.

Sebastian blew out the candles, shrouding the room in darkness once more.

After he was done, the boy would almost be too good to eat. _Almost._


End file.
